1. Field of the Invention
This application is directed to lasers and to output windows for use therewith.
2. Discussion of the Prior Art
Multicapillary arrays (MCA's) made of perforated stainless steel plates have been previously reported (see P. D. Chopra, et al., J. Phys. B7, 2421 (1974)) as useful in transmitting radiation at 1216 A although no details of the properties of the arrays were given. In recent years the technology of producing glass MCA's having capillaries of very small diameters, tightly packed in arrays giving large spatial apertures, has been developed in connection with the development of multichannel plate image intensifiers. These arrays are now commercially available from Galileo Electro-Optics Corp., Sturbridge, Mass. Most of these arrays have open areas in excess of 50%, are available with pore sizes between 1.5 .mu.m and 100 .mu.m, and can be fabricated in sizes in excess of 10 cm.sup.2. These windows have been used to separate a vacuum spark (BRV-type) VUV (vacuum ultraviolet) source and an evacuated, grazing incidence, optical system from a .about.10.sup.3 .mu.bar vapor cell to obtain atomic absorption spectra in the 100-400 A spectral region, see T. B. Lucatorto and T. J. McIlrath, Physics Review Letters, Vol. 37, No. 7, pp. 428-431 (1976). They were also used as an output window on a gas discharge VUV light source in the 400-1050 A spectral region, see T. V. Vorburger, et al., Rev. Sci. Instrum., Vol. 47, p. 501 (1976). In these foregoing experiments the flat glass surface which alternates with the clear aperture of the array was not used for any purpose. MCA applications including the application of the present invention are also discussed in an article by the present inventors, see Applied Optics, Vol. 18, page 2505, July 15, 1979. All of the foregoing articles are incorporated herein by reference.